Energy in the form of electricity can be stored in the form of hydrogen, for example, by applying the electricity to an electrolysis process to disassociate the hydrogen from oxygen in water. Energy in the form of heat can also be stored in the form of hydrogen by using a thermal conversion process to dissociate the hydrogen from oxygen in water.
Hydrogen can be incorporated into a metal hydride. Later, the hydrogen can be released by mixing water with the metal hydride and used to provide energy, for example, to a car. Magnesium and hydrogen can be converted into magnesium hydride using temperatures of 500° C. or higher and pressures of 200 atmospheres or higher. Catalysts can reduce the required temperatures and pressures.